Performance Evaluation of a Vertical U-Tube Ground Heat Exchanger Using a Numerical Simulation Approach

Abstract:

A vertical U-tube ground heat exchanger can be utilized to exchange heat with the soil in ground source heat pump systems. The outlet temperature of the working fluid through the U-tube not only accounts for heat transfer capacity of a ground heat exchanger, but also greatly affects the operational efficiency of heat pump units, which is an important characteristic parameter of heat transfer process. It is quantified by defining a thermal effectiveness coefficient. The performance evaluation is performed with a three dimensional numerical model using a finite volume technique. A dynamic simulation was conducted to analyze the thermal effectiveness as a function of soil thermal properties, backfill material properties, separation distance between the two tube legs, borehole depth and flow velocity of the working fluid. The influence of important characteristic parameters on the heat transfer performance of vertical U-tube ground heat exchangers is investigated, which may provide the references for the design of ground source heat pump systems in practice.

• Periodical: Advanced Materials Research (Volumes 724-725)
• Pages: 909-915
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.724-725.909
• Online since: August 2013
• Authors: Ping Fang Hu, Zhong Yi Yu, Fei Lei, Na Zhu, Qi Ming Sun, Xu Dong Yuan
• Keywords: Ground Heat Exchanger, Ground Source Heat Pump (GSHP), Numerical Model, Thermal Effectiveness Coefficient

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